The present invention relates generally to novel abrasive cutting tools and their method of manufacture and particularly concerns a novel multi-disc cutter, its method of manufacture and its use in the manufacture of ink jet printheads.
Copending application Ser. Nos. 140,617 and 140,764, both filed Jan. 4, 1988 and both entitled DROPLET DEPOSITION APPARATUS, disclose ink jet printheads having a plurality of linear, parallel ink cavities or channels formed in a pre-poled piezoelectric ceramic. In order to provide a printhead having the desired operating characteristics and print resolution, the dimensions of the ink cavities are quite small and their tolerances must be precisely controlled. A typical printhead may, for example, have ink cavities which are about 30-200 microns wide by 150-1000 microns deep and a cavity pitch of about 75-500 microns. Due to the linear cutting speeds achievable, the possibility of channel depth profiling and the manufacturing tolerances required, the use of diamond cutting tools is presently preferred to form the ink cavities. While a number of such tools are currently available, their is a need for a more efficient tool, particularly for use in a mass production environment.
A known prior art technique of forming tools of various configurations is that of laser ablation. For example, U.S. Pat. Ser. No. 4,533,812 teaches the use of a laser to shape a diamond grinding disc and U.S. Pat. Ser. No. 4,170,726 teaches the use of a laser to form a workpiece by melting selected areas of the workpiece and then removing the resulting melt. None of the known prior art techniques, however, are considered satisfactory for the purpose of forming diamond cutting tools suitable for use in the mass production of ink jet printheads, especially printheads having ink cavities with the precisely controlled and extremely fine dimensions described above.